Re: [Dump-users] Incremental Backups

[Stelian P. <st...@po...>]

On Mon, Jan 12, 2009 at 08:14:43PM -0500, Bruce Hyatt wrote:

> Keith G. Robertson-Turner wrote:
> 
> >Here's what you should be doing (IMHO):
> >
> > Day     | Level | Set
> > -------------------------
> > 1       | 0     | 1
> > 2       | 1     | 1
> Etc.
> 
> Thanks, Keith.
> 
> I'll try this. It looks simpler than the "tower of Hanoi" at least.

It does look simpler but the advantage of the tower of Hanoi way is that
it minimizes the number of tapes you need to restore in case of data
failure.

Imagine you do a level 0 dump on Sunday, 1 on Monday, 2 on Tuesday etc,
and that the failure occurs on Saturday. In this case you will need to
restore the level 0, 1, 2, 3, 4, 5, 6 tapes (Friday being the last known
good tape - number 6).

If you use the tower of Hanoi sequence you would have to restore only 3
or 4 tapes at the most.

Stelian.
-- 
Stelian Pop <st...@po...>